The goals of the four-day, 62-orbit mission were numerous and daring. While Gemini III, the first human flight of the series, completed 3 orbits and lasted under 5 hours, the Gemini IV mission tested procedures for longer journeys into space.

The mission also demonstrated new maneuvers and a series of experiments performed by McDivitt and White, including an attempted rendezvous with Gemini IV’s Titan launch vehicle. (The rendezvous attempt was not successful.)

On the first day of the flight, White completed the first American spacewalk. The extravehicular activity, which lasted for 21 minutes, tested the new space suit designed for spacewalks and the Hand-Held Maneuvering Unit (HHMU), a device that was intended to control the astronaut’s movements in space.

It rapidly used up the propellant supply and was not as effective as expected, so the HHMU hardware was abandoned after this mission. White was attached to the ship by a 25-foot cord, which also contained oxygen supply and communication lines.

When prompted to return to the spaceship, White replied “I’m coming back in…and it’s the saddest moment of my life.”

The goals of the four-day, 62-orbit mission were numerous and daring. While Gemini III, the first human flight of the series, completed 3 orbits and lasted under 5 hours, the Gemini IV mission tested procedures for longer journeys into space. (NASA Image)

The mission also demonstrated new maneuvers and a series of experiments performed by McDivitt and White, including an attempted rendezvous with Gemini IV’s Titan launch vehicle. (The rendezvous attempt was not successful.) (NASA Image)